Update to new temporary default paramfile for clm6_0

Author: slevis-lmwg

bld/namelist_files/namelist_defaults_ctsm.xml

@@ -530,7 +530,7 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
 <!-- The default filenames are given relative to the root directory
      for the CLM2 data in the CESM distribution -->
 <!-- Plant function types (relative to {csmdata}) -->
-<paramfile phys="clm6_0" >lnd/clm2/paramdata/ctsm60_params.c250311.nc</paramfile>
+<paramfile phys="clm6_0" >lnd/clm2/paramdata/ctsm5.3.041.Nfix_params.v13.c250221_upplim250.nc</paramfile>
 <paramfile phys="clm5_0" >lnd/clm2/paramdata/clm50_params.c250311.nc</paramfile>
 <paramfile phys="clm4_5" >lnd/clm2/paramdata/clm45_params.c250311.nc</paramfile>